The present invention relates to a vise for clamping a workpiece. In particular, the vise of the present invention includes means for exerting a downward force upon the workpiece when the workpiece is clamped against a stop.
The prior art has advanced many types of vises for holding workpieces to be machined. Commonly, these vises include a moveable clamping member having a clamping surface for clamping the workpiece against a suitable stop. Simply clamping the workpiece with forces reacted between the stop and the clamping member, however, is not preferred. Rather, there is a need to also generate holddown forces which urge the workpiece downwardly against a platen working surface. The holddown forces counteract a tendency of the workpiece to lift during clamping and machining.
Some prior art vises have attempted to produce both clamping and holddown forces. For instance, U.S. Pat. No. 4,345,750 issued to Glaser discloses a sliding block used to clamp a workpiece against an abutment. The sliding block is urged toward the abutment by a threaded drive screw. The sliding block has a pin and a wedge located therein. The wedge has a flat surface that contacts a flat surface of the pin at a 45.degree. angle. An end of the drive screw contacts the wedge at an end opposite the pin to drive the sliding block toward the abutment. However, since both the pin and the wedge are located in the same sliding block, holddown forces do not exist.